Purpose: Corticosteroids are commonly injected into the joint space. However, studies have not examined the chondrotoxicity of one-time injection doses. The purpose of this study is to evaluate the effect of dexamethasone sodium phosphate (Decadron), methylprednisolone acetate (Depo-Medrol), betamethasone sodium phosphate and betamethasone acetate (Celestone Soluspan), and triamcinolone acetonide (Kenalog) on human chondrocyte viability in vitro.

Methods: Single-injection doses of each of the corticosteroids were separately delivered to human chondrocytes for their respective average duration of action and compared to controls using a bioreactor containing a continuous infusion pump constructed to mimic joint fluid metabolism. A 14-day time-controlled trial was also performed. A live/dead reduced biohazard viability/cytotoxicity assay was used to quantify chondrocyte viability.

Results: Over their average duration of action, betamethasone sodium phosphate/acetate solution and triamcinolone acetonide caused significant decreases in chondrocyte viability compared to control media (19.8 ± 2.9% vs. 5.2 ± 2.1%, P = 0.0025 and 10.2 ± 1.3% vs. 4.8 ± 0.9%, P = 0.0049, respectively). In the 14-day trial, only betamethasone sodium phosphate/acetate solution caused a significant decrease in chondrocyte viability compared to control media (21.5% vs. 4.6%, P < 0.001).

Conclusions: A single-injection dose of betamethasone sodium phosphate and betamethasone acetate solution illustrated consistent and significant chondrotoxicity using a physiologically relevant in vitro model and should be used with caution. Given the observed chondrotoxicity of triamcinolone acetonide in a single trial, there may be some evidence that this medication is chondrotoxic. However, at 14 days, betamethasone sodium phosphate and betamethasone acetate was the only condition that caused significant cell death.